Executive Summary ...67 2.1. Introduction and Scope...69 2.2. Defining Determinants of Risk: Hazard, Exposure, and Vulnerability ...69
2.2.1. Disaster Risk and Disaster ...69 2.2.2. The Factors of Risk ...69
2.3. The Drivers of Vulnerability ...70 2.4. Coping and Adaptive Capacities ...72
2.4.1. Capacity and Vulnerability ...72 2.4.2. Different Capacity Needs ...74 2.4.2.1. Capacity to Anticipate Risk...74 2.4.2.2. Capacity to Respond...74 2.4.2.3. Capacity to Recover and Change...75 2.4.3. Factors of Capacity: Drivers and Barriers...76
2.5. Dimensions and Trends of Vulnerability and Exposure ...76
2.5.1. Environmental Dimensions...76 2.5.1.1. Physical Dimensions ...77 2.5.1.2. Geography, Location, Place ...77 2.5.1.3. Settlement Patterns and Development Trajectories...78 2.5.2. Social Dimensions ...80 2.5.2.1. Demography ...80 2.5.2.2. Education...81 2.5.2.3. Health and Well-Being ...82 2.5.2.4. Cultural Dimensions...84 2.5.2.5. Institutional and Governance Dimensions ...85 2.5.3. Economic Dimensions...86 2.5.4. Interactions, Cross-Cutting Themes, and Integrations ...87 2.5.4.1. Intersectionality and Other Dimensions...88 2.5.4.2. Timing, Spatial, and Functional Scales ...88 2.5.4.3. Science and Technology ...89
2.6. Risk Identification and Assessment ...89
2.6.1. Risk Identification ...90 2.6.2. Vulnerability and Risk Assessment...90 2.6.3. Risk Communication...95
2.7. Risk Accumulation and the Nature of Disasters ...95 References ...96
Table of Contents
The severity of the impacts of extreme and non-extreme weather and climate events depends strongly on the level of vulnerability and exposure to these events (high confidence). [2.2.1, 2.3, 2.5] Trends in vulnerability and exposure are major drivers of changes in disaster risk, and of impacts when risk is realized (high confidence). [2.5]
Understanding the multi-faceted nature of vulnerability and exposure is a prerequisite for determining how weather and climate events contribute to the occurrence of disasters, and for designing and implementing effective adaptation and disaster risk management strategies. [2.2, 2.6]
Vulnerability and exposure are dynamic, varying across temporal and spatial scales, and depend on economic, social, geographic, demographic, cultural, institutional, governance, and environmental factors (high confidence). [2.2, 2.3, 2.5] Individuals and communities are differentially exposed and vulnerable and this is based on factors such as wealth, education, race/ethnicity/religion, gender, age, class/caste, disability, and health status. [2.5]
Lack of resilience and capacity to anticipate, cope with, and adapt to extremes and change are important causal factors of vulnerability. [2.4]
Extreme and non-extreme weather and climate events also affect vulnerability to future extreme events, by modifying the resilience, coping, and adaptive capacity of communities, societies, or social-ecological systems affected by such events (high confidence). [2.4.3] At the far end of the spectrum – low-probability, high-intensity events – the high-intensity of extreme climate and weather events and exposure to them tend to be more pervasive in explaining disaster loss than vulnerability in explaining the level of impact. But for less extreme events – higher probability, lower intensity – the vulnerability of exposed elements plays an increasingly important role (high confidence). [2.3] The cumulative effects of small- or medium-scale, recurrent disasters at the sub-national or local levels can substantially affect livelihood options and resources and the capacity of societies and communities to prepare for and respond to future disasters. [2.2.1, 2.7]
High vulnerability and exposure are generally the outcome of skewed development processes, such as those associated with environmental mismanagement, demographic changes, rapid and unplanned urbanization in hazardous areas, failed governance, and the scarcity of livelihood options for the poor (high confidence). [2.2.2, 2.5]
The selection of appropriate vulnerability and risk evaluation approaches depends on the decisionmaking context (high confidence). [2.6.1] Vulnerability and risk assessment methods range from global and national quantitative assessments to local-scale qualitative participatory approaches. The appropriateness of a specific method depends on the adaptation or risk management issue to be addressed, including for instance the time and geographic scale involved, the number and type of actors, and economic and governance aspects. Indicators, indices, and probabilistic metrics are important measures and techniques for vulnerability and risk analysis. However, quantitative approaches for assessing vulnerability need to be complemented with qualitative approaches to capture the full complexity and the various tangible and intangible aspects of vulnerability in its different dimensions. [2.6]
Appropriate and timely risk communication is critical for effective adaptation and disaster risk management (high confidence). Effective risk communication is built on risk assessment, and tailored to a specific audience, which may range from decisionmakers at various levels of government, to the private sector and the public at large, including local communities and specific social groups. Explicit characterization of uncertainty and complexity strengthens risk communication. Impediments to information flows and limited awareness are risk amplifiers. Beliefs, values, and norms influence risk perceptions, risk awareness, and choice of action. [2.6.3]
Adaptation and risk management policies and practices will be more successful if they take the dynamic nature of vulnerability and exposure into account, including the explicit characterization of uncertainty and complexity at each stage of planning and practice (medium evidence, high agreement). However, approaches to representing such dynamics quantitatively are currently underdeveloped. Projections of the impacts of
Executive Summary
climate change can be strengthened by including storylines of changing vulnerability and exposure under different development pathways. Appropriate attention to the temporal and spatial dynamics of vulnerability and exposure is particularly important given that the design and implementation of adaptation and risk management strategies and policies can reduce risk in the short term, but may increase vulnerability and exposure over the longer term. For instance, dike systems can reduce hazard exposure by offering immediate protection, but also encourage settlement patterns that may increase risk in the long term. [2.4.2.1, 2.5.4.2, 2.6.2]
Vulnerability reduction is a core common element of adaptation and disaster risk management (high confidence). Vulnerability reduction thus constitutes an important common ground between the two areas of policy and practice. [2.2, 2.3]
2.1. Introduction and Scope
Many climate change adaptation efforts aim to address the implications of potential changes in the frequency, intensity, and duration of weather and climate events that affect the risk of extreme impacts on human society. That risk is determined not only by the climate and weather events (the hazards) but also by the exposure and vulnerability to these hazards. Therefore, effective adaptation and disaster risk management strategies and practices also depend on a rigorous understanding of the dimensions of exposure and vulnerability, as well as a proper assessment of changes in those dimensions. This chapter aims to provide that understanding and assessment, by further detailing the determinants of risk as presented in Chapter 1.
The first sections of this chapter elucidate the concepts that are needed to define and understand risk, and show that risk originates from a combination of social processes and their interaction with the environment (Sections 2.2 and 2.3), and highlight the role of coping and adaptive capacities (Section 2.4). The following section (2.5) describes the different dimensions of vulnerability and exposure as well as trends therein.
Given that exposure and vulnerability are highly context-specific, this section is by definition limited to a general overview (a more quantitative perspective on trends is provided in Chapter 4). A methodological discussion (Section 2.6) of approaches to identify and assess risk provides indications of how the dimensions of exposure and vulnerability can be explored in specific contexts, such as adaptation planning, and the central role of risk perception and risk communication. The chapter concludes with a cross-cutting discussion of risk accumulation and the nature of disasters (Section 2.7).